Off-the-Shelf Hardware
ArduAqua is built using standard, widely available electronics components. No proprietary hardware is required.
Main Components
- Arduino Mega 2560 - The heart of the system.
- LCD Keypad Shield (16x2) - Classic HD44780 interface.
- DS3231 RTC + AT24C - High-precision clock with EEPROM.
- DS18B20 Sensors - At least 1 (Tank), others optional.
- Pull-up Resistor - 4.7kΩ for the temperature bus.
- Relay Module (Optional) - Needed for heaters or 230V devices.
- Buttons - 4x push buttons.
Wiring: Fixed Assignments
These ports are reserved for specific hardware functions. Most other pins can be freely assigned in the menu.
| Function | Mega Pin(s) |
|---|---|
| LCD Display (via Shield) | 4, 5, 6, 7, 8, 9, 10 |
| Buttons | A10 - A13 |
| LED PWM (7 Channels) | 2, 3, 11, 12, 44, 45, 46 |
| All Other Pins | Freely assignable for Sensors, Pumps, Relays, etc. |
Custom Button Module
A self-made button module is required. Standard LCD shield buttons use resistor coding which is too imprecise and doesn't support the hardware interrupt needed to wake the device from standby.
Sensor Authenticity
Most DS18B20 sensors on the market are clones. ArduAqua can detect these and displays 'B' (Backup/Clone) or 'O' (Original) in the info menu. Both work, but originals are more precise.
Relay Safety & Inrush
For 230V wiring, consulting an electrician is mandatory. Cheap modules often have dangerously small isolation distances; look for PCBs with physical cutouts. Also note that high inrush currents from switching power supplies can 'weld' relay contacts shut over time.
Dosing System
Control up to 16 pumps. The system handles calibration automatically: just measure the output once, and ArduAqua calculates the exact timings for your required dosage.
Firmware Architecture
Written in C++ for AVR, the firmware uses a non-blocking event loop and hardware interrupts for high-priority tasks. Settings are stored in the external AT24C EEPROM (RTC module) to minimize wear on the Mega's internal memory.